The odd (literally) attenuation of the EVG-043 spectral frequencies in its forward wave signature really perplexed me ever since I discovered it.

Over the last several days, I've been busy with holiday stuff and trips to the stores. I also did an oil change on my mom's car, soldered some more wires on my car where a chipmunk decided to munch, and installed a new door handle assembly on the bathroom door. I'm not a carpenter, but I had to chisel out a recess on the door for the new striker plate and one on the jam for the old one. Works good!

This did give me a break and time for my mind to 'mull over' the present scenario. I thought "the only plausible explanation for attenuation is a wave form vibrating out of phase with the fundamental et alii. But from where?"

Then it hit me last night ... it's the vibratory motion of the pulse jet relative to the support cradle and its motion relative to the base. Simple.

Thanks again for your interest in my project of some years ago (a duplicate of the now-famous Kentfield motor, with 4 intakes); your analysis and subsequent positive recommendation provided me with incentive to build a successful version of my own, and to develop and build a number of successors afterward.

The current question I have is, are you willing and able to distill the current development of your successful analysis of a "strip-valve" type intake, so we (the great unwashed) can take advantage of your discovery? There must be an eventual empirical solution that would satisfy the far more complex math you're currently working with. You could attach a limitation which would allow you to participate in any commercial application of your concept--or I'm sure there's other arrangements which would satisfy you as the source of this development. I've become a convert to the concept of "open-source" info such as this--and you would probably enjoy the fruits of real-life developments as they are likely to occur, to validate your concepts and possibly further them.

I'm enjoying the electrical theories you're applying as an analog to your solutions; in the fall of 1964 I was at UC Berkeley as a scholarship student and encountered the same concept in my Physics 1A class. Shades of my youth there!!

All the best of success in your current and future efforts.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

If I remember correctly, I never did hear from you again after I performed that analysis.

Now you ask for my Valve Glide™ technology?

No, I won't do as you ask; what you did before won't happen a second time.

~°~~°~~°~

G.,

When I first got your video, I played it over and over again in the back ground on my desktop. You have to look hard, but between 2-3 sec event time, you'll see an almost imperceptible (vector) movement to the right!

It's all a matter of seeing, isn't it?

~°~~°~~°~

OK, I don't mean to torture you, my readers, with more math, but this concept is important. If you have never taken a vibrations course, you are going to learn something quite fundamental now.

No torture, Forrest. I like where this is going a lot. Test stands can be so bad and the experimenter may have no idea why he's getting whacky readings. He may just conclude that his beautiful little motor has no thrust at all!

Mike Everman wrote:No torture, Forrest. I like where this is going a lot. Test stands can be so bad and the experimenter may have no idea why he's getting whacky readings. He may just conclude that his beautiful little motor has no thrust at all!

Hi Mike

Yes agreed to that and its counterpoint for results, the application of Forrest's rigor is perfectly applicable to thrust benches of all types

Viv

"Sometimes the lies you tell are less frightening than the loneliness you might feel if you stopped telling them"Brock Clarke

Of course, the counterpoint being that you can think you have much more thrust than you have. I've always wanted to make a mount that had a tunable natural frequency, and to watch the thrust gage change just by changing the stiffness of the mount, and/or the mass.

All I was setting out to do was to attempt to explain why the spectral frequencies of the waveform emanating from the front of the pulsejet are attenuated. This can be done by use of the concept of equivalent stiffness and driving frequency ratio.

That is, if I get the chance to put it up here. Hopefully, as it evolves, your questions will be answered.

I'll interrupt my present train of thought and back up a bit.

The above is not the only way, but it is a drawing of what I consider to be the essential requirements that must be addressed.

the pj is mounted via cantilever arms secured to a flat cradle plate. No matter how stiff the upright cantilevers are made, there is going to be some vibratory movement of the pj relative to the cradle. I have drawn this using gray lines.

the cradle rests on 4 rollers (only 2 are shown) to provide support in the upright direction and a smooth action in the for and aft directions (vector). The spring scale is attached at the aft end and a pin hole is drilled in the front. The pin essentially 'shunts' the spring; thus, making a semi-rigid connection between cradle and base.

another roller is attached to each of the forward roller mounts so that the roller rests on the upper surface of the cradle. Similarly another pair are attached to the aft roller mounts. These provide the resisting moment due to a fluctuating gauge pressure inside the pj combustion chamber causing a force directed to the right (+tive gauge pressure) and to a lesser amount to the left (-tive gauge pressure).